Transit concrete mixer having adjustable discharge height



Dec. 12, E950 B. F. DEVINE ETAL 2,533,362

TRANSIT CONCRETE MIXER HAVING ADJUSTABLE DISCHARGE HEIGHT Filed Dec. 10, 1947 3 Sheets-Sheet l N k N & Q

BERNARD Fv DEVINE LOUIS G. HILKEMEIER INVENTORS y ORNE Dec. 32, 1950 B. F. DEVINE ET AL 2,533,362

TRANSIT CONCRETE MIXER HAVING ADJUSTABLE DISCHARGE HEIGHT Filed Dec. 10, 1947 s Sheets-Sheet 2 RESERVOIR BERNARD F. DEVINE LOUIS 6.,HIL'KEMEIER INVENTORS Dec" 112 1950 B. F. DEVINE ETAL 2,533,362

TRANSIT CONCRETE MIXER HAVING ADJUSTABLE DISCHARGE HEIGHT Filed Dec. 10, 1947 3 Sheets-Sheet 3 BERNARD F. DEVINE LOUIS e. HILKEMEIER INVENTORS BY 4- {WM ATTORNEY Patented Dec. 12, 1950 TRANSIT CQNCRETE DHXER HAVING ADJUSTABLE DISCHARGE HEIGHT Bernard F. Devine, /Vauwatosa, and Louis G. Hilkemeier, Greenfield, Wis, assignors to Chain Belt Company, Milwaukee, Wis a corporation of Wisconsin Application December 10, 1947, Serial No. 790,738

4 Claims. i

This invention relates to supporting and e1evating means for concrete mixers such as are mounted on motor trucks to transport and to mix or agitate concrete in transit.

It is a primary object of the present invention to provide more stable and less costly apparatus whereby the discharge height of the mixer drum may be adjusted to meet different requirements.

Heretofore transit concrete mixers have been principaly of two types: the horizontal type and the inclined axis type, depending on whether the fixed axis of the mixer drum, which lies parallel to the length of the truck, is horizontal in one case or, in the other case, inclined with the discharge end elevated. The inclined axis type has the advantage that discharge from the annular opening in the end of the drum may be from a higher and hence more useful position.

The horizontal type mixer has compensating advantages however, especially in regard to producing adequate mixing, lower center of gravity for transportation, faster charging and economies in manufacture and maintenance. The principal advantage of the horizontal type in regard to mixing resides in the fact that with the axis horizontal, there is more free space above the ingredients for the full length of the drum within which the ingredients of the mix may be tumbled, whereas with the inclined axis drum, the ingredients tend to pile up in the lower, closed end of the drum, thus eliminating any free mixing space in this region. The cone portions of the inclined axis drum aso retard mixing, as compared with the horizontal drum, which is largey cylindrical, and hence has a greater diameter for a greater portion of its length.

The advantages of mixing in a drum rotating about a horizontal axis and discharging while rotating the drum about an inclined axis have likewise been recognized in the art, and appara- 1 bus for tilting the drum from a horizontal axis, mixing position to an inclined axis, discharging position have been disclosed in patents and actually commercialized. An illustration of such apparatus is Patent No. 1,998,749 issued April 23,

used: first is the excessive initial cost; second the tendency of the drum to overturn when the discharge is elevated; third the excessive weight; and finally the fact that the hoisting mechanism which is involved must be adapted to fit different i 2 types of trucks and different types of mixers thus making standardization and volume production extremely diflicult.

It is an object of the present invention to provide apparatus by which the mixing drum can be carried in a horizontal position at a lower height and yet its discharge end can be raised with more case than in apparatus heretofore known. It is a great advantage to carry the drum at a lower level when it is horizontal, not only because of less possibility of overturning the drum when it is transported and mixing, but also because when the discharge end is elevated, and possibly on sloping ground, the danger of tipping over sidewise is considerably minimized.

A further object of the invention is to provide apparatus for elevating the concrete mixer as aforesaid, which is considerably lighter in weight and permits the trucks to carry heavier loads of concrete than was formerly possible.

In the aforesaid Ball patent, the mixer drum is driven by a separate engine in preference to a power take-off drive from the truck, but the power for operating the hoist is derived from the truck power transmission.

According to the present invention, the power for operating the hoist is also derived from the engine that drives the mixer drum, and the entire apparatus for hoisting the drum is mounted on the mixer frame.

The present invention has notable advantages, aside from the elimination of the power take-off on the truck transmission, for it enables the mixer manufacturer to furnish as standard equipment all the elements necessary to be mounted on the truck and permits the mounting operation to be performed in a simplified and less expensive manner.

Utilizing the engine that drives the mixer drum to operate the hoist makes it possible to stop the truck engine when the truck is in posi tion at the construction site, thus saving on motor fuel, and utilizing the horsepower available on the mixer engine which is normally running at this time.

A preferred embodiment of the present invention is illustrated in the accompanying drawings wherein:

Fig. 1 is a side elevation of the mixer and its supporting mechanism;

Fig. 2 is an end view of the apparatus shown in Fig. 1;

Fig. 3 is an enlarged view, partly in section, of one of the hinges at the forward end of the mixer;

Fig. 4 is a side elevation of the apparatus shown in Fig. 3;

Fig. 5 is a diagrammatic view of the hydraulic system employed with the present invention;

Fig. 6 is a diagrammatic view of the mixer drum in horizontal position; and

Fig. 7 is a diagrammatic view of the mixer drum in discharge position with its axis inclined.

Referring to Fig. l of the drawing, the motor truck I i is provided with the usual side frame members [2 on which the transit concrete mixer is mounted behind the cab of the truck. The mixer is supported on a frame generally designated i3 having lower side sills M which are arranged for position directly above the side frame members [2 of the truck. The mixing drum I5 is disposed to rotate about a horizontal axis with the front end of the drum supported by an axially disposed trunnion journalled in a bearing mounted at the front of the frame l3. The front end of the drum is closed and its method of support on the axial bearing is well known in the art and need not be described in greater detail.

In the side of the drum there is provided an opening indicated at if: which is normally closed by a removable hatch door. When the drum is rotated to the position shown in Fig. 1, the hatch door may be removed and the dry ingredients of the mix are charged through the opening, after which the door is put back in place, and the drum can be rotated to mix the materials.

The rear of the drum is provided with an axial opening to which a rim E7 is secured as an extension. Rim :7 serves as a track, for it rests on rollers 18 which are mounted in plates l9 extending between the rear upright members 28 of the frame 13. The opening at the rear of the drum is controlled by a door 2! slidably mounted on a shaft extending from the interior of the drum. Mechanism for actuating the door 2| is indicated by the linkage 22 and the hand wheel 23. This latter mechanism may well take the form illustrated in Patent No. 2,231,823 issued on February 11, 1941, entitled Closure Mechanism for Concrete Mixer Receptacles.

A tank 25 is provided at the front of the machine and provides an adequate supply of water for mixing in transit or at the job's site. Water from the tank 26 is forced by the pump 2'! through an opening in the trunnion that supports the forward end of the drum and is dispelled into the dry materials in the drum by a suitably located water nozzle.

Power for turning the drum about its horizontal axis and for driving the water pump 2? is derived from a separate engine 28 mounted on the frame is of the mixer, any suitable driving mechanisms being permissible, but preferably a chain drive as the final drive to the mixer drum. Within the drum are blades designed to tumble the materials and to propel them from one end of the drum to the other depending, upon the direction in which the drum is rotated. Normally during mixing the drum is rotated so that the materials are moved toward the forward. closed end of the drum, the conical side walls 29 in this region facilitating the return to the 'rear of the drum of the materials so propelled. When it is desired to discharge the mixed batch of concrete, blades in the rear portion of the drum which are more or less in the shape of buckets force the material through the. opening formed by the rim ii, the rear door 2| having been retracted for this purpose.

The mixed concrete expelled through the discharge opening is received in the gathering chute 39 and directed to the distributing chute 3|. The higher the discharge opening can be elevated the farther the concrete can be conveyed by the distributing chute 3!, which is disposed below the gathering chute 30. In Fig. l the dotted line position of certain of the elements illustrates the increase in height of the discharge opening which can be effectuated by the present invention, as will be hereinafter described.

As illustrated .in Figs. 3 and 4 an angle iron 34 is arranged transverse to and placed across the two side frame members l2 of the truck. An angle iron 35 welded to the angle iron 34, extends only across the width of each of the frame members 12. Angle iron 35 is drilled to accommodate a pair of long bolts 36, one arranged on each side of the members [2, and these bolts depend below the bottom of the truck side frame members. A third bolt 31 is likewise provided extending through the angle iron 34 at the inner side of the frame members l2. and a triangular retaining plate 38 extending across the bottom of the frame member I2 and through which the bolts 36 and 37 extend, co-operates with the nuts 33 which are threaded on the aforesaid bolts. In this manner, the cross member 34 may be firmly secured to the frame of the truck.

Secured to the rearward side of the vertical portion of the angle iron 34 are a pair of spaced cars 40 which house the pin M extending therebetween. The pin AI is locked in place by a keeper 42 which is securely fastened to the end of the pin extending beyond the outer ear 49 and which is provided with a set screw 43 which may be threaded into a tapped hole in the adjacent ear.

Journalled on the pin 41 and extending between the ears lil is a tongue 45 which is welded or otherwise rigidly secured to the side sill ll of the mixer frame. Normally the side sills N are made from Z-bars, but these bars may be suitably reinforced by angle irons 47 mounted on their inner side as illustrated in Fig. 2. to lend greater rigidity to the structure.

It will be appreciated that the hinge structure at either side of the front of the two side sills of the mixer frame is the same, and that the hinges are aligned so that the entire mixer frame may be pivoted to the desired discharge position.

At the rear of the truck there is also provided a transverse angle iron 48 one flange of which is horizontal and extends across the top of the two side frame members [2. The other flange of the angle iron 48 is vertical and abuts the ends of the frame members 12. The angle iron 48 is secured to the truck frame by the two sets of bolts 49 which are arranged on each side of the frame channels l2, said bolts extending through the retaining plates 50, as is clearly illustrated in Fig. 2.

At each end of the outer extremities of "the cross member 58, i. e. the portions that extend beyond the side frame members [2, are hinges formed by pins 5i and the spaced upstanding ears 52 in which these pins are mounted. The cars 52 are rigidly secured to the cross member 48 preferably by welding. Similar hinges are provided in substantially vertical alignment with the last mentioned hinges through the provision of brackets 53 mounted on the outer sides of the rear upright members Ail of the mixer frame. In the latter case the ears 54 depend from the lower side of the brackets and the pins 55 which they carry are parallel to the pins 5: which are mounted on the truck frame.

'ing a suitable eye portion 5'; for journalling on the pins 55.

The eyes 58 on the ends of the piston rods associated with each ram are journalled on the pins 5! which are mounted on the truck frame. I

It might be well to point out here the advantages obtained from the disposition of the rams in the manner aforesaid. In Fig. 6 there is illustrated the position of the mixer when the axis of the drum is horizontal, the letter A designating the approximate center of gravity of the drum when it is loaded with a normal size batch of aggregates. The position of this center of :gravity will vary depending on the size of the charge, the rams are in a most eiiective position to resist the torque developed by the rotating drum.

The disposition of the rams outside the rear uprights as illustrated in Fig. 2, also lends increased stability to the elevated drum, the drum being cradled between the hydraulic rams. This is a factor in making more uniform the pressure on the two rams despite the shifting of the center of gravity to one side of the axis of the drum incident to material piling up on that side of the drum as the drum revolves, augmented possibly by the slope of the ground On which the truck may be resting.

Energy for operating the rams 56 is derived from a pump 59 which may conveniently be driven from the shaft that operates the water pump 21, which in turn is driven by the mixer engine 23. Of course the pump 59 may be driven directly by the engine 28. The hydraulic diagram is illustrated in Fig. 5, according to which fluid -for the pump 59 is derived from a reservoir 63 and the flow to the two rams is equalized by the flow equalizer designated 5! This latter member may be of the hydraulic gear type such as is readily available on the open market, and will not be described in detail herein. The equalizer will apportion to each of the ram cylinders the same quantity of fluid in order that both rams will extend at the same rate despite the fact that the truck may be on uneven ground and one a ram may be carrying a heavier load than the other. Hence the mixer frame will be kept parallel to the truck and twisting of the two frames is avoided.

Since the fluid pump will be constantly running it is desirable to by-pass the hydraulic fluid to the reservoir when the rams are not in operation and hence the control valve 62 which is conveniently mounted at the rear of the mixer frame is of the three-way type so that when in neutral position the fluid pressure line from the pump connects directly to the return line leading to the reservoir and the pump. When it is desired to elevate the rear of mixer frame the control valve lever 63 is shifted to its "up posi-= tion puttin the pressure line in communication with the line leading to the flow equalizer, where'- upon the rams are extended. To lower the mixer drum to its normal horizontal position the control valve is shifted to its down position in which the line leading to the flow equalizer is placed in communication with the return line to the reservoir, and the weight of the mixer forces the oil out of the hydraulic rams during the lowering operation.

Oil reservoir 66 is conveniently mounted above the hydraulic pump 59 adjacent to the water tank 26 and the pressure and return lines designated 54 and 65 respectively leading to the control valve 62 may be permanently mounted on the mixer frame. The flow equalizer 6| may likewise be mounted on the mixer frame and the only flexible hoses that are necessary are those designated 66 that connect the ends of the pipes 6! from the flow equalizer with the operatin portion of the rams. If flexible couplings are used at the juncture of the pipes 8i and the ram cylinders, even this flexible tubing may be dispensed with.

It will be appreciated that the only time the rear end of the mixer will be elevated is when the drum contents are being discharged and that during transportation and mixing, the axis of the drum will be in a horizontal position. To relieve the rams 56 and their hinged connections from side strains and other forces when the mixer drum is in horizontal position a pair of upstanding guides 58 are secured to the back of the angle iron 48. As illustrated in Fig. 2, the upper portions of the guides 68 turn outwardly so that the side sills is of the mixer frame may be steered between them and may be held against side thrust as the mixer frame is lowered into transporting position. Pads 59 welded to the under side of the side sills l4 limit the downward movement or" the mixer frame as it hinges about. the forward pins l.

That the entire mixer and its hoisting mechanism can be readily assembled on the truck and that the truck need be provided with no special equipment to accommodate the mixer will be clearly appreciated from the foregoing description.

It will likewise be appreciated that the rams need not be extended to their full length in all discharge operations. The present invention provides improved apparatus for elevating the discharge opening to various positions. Of course in many instances, there will be no necessity of elevating the discharge end at all.

The apparatus illustrated in the drawings is adapted to transport pro-mixed concrete as well as to mix such concrete either at the job site or in transit. When the concrete is mixed prior to its being placed in the mixing receptacle, it may or may not be necessary to rotate the receptacle during transportation. The discharging of the batch from the receptacle naturally produces some agitation.

The invention having been described, what is claimed is:

l. .A self-contained concrete mixing or agitatinc unit for tiltable mounting upon the chassis of road vehicle without modification of such chassi raid unit comprising a frame including a pair of transversely spaced longitudinal sills -disposable directly upon said chassis, and similarly spaced vertical members extending upwardly from the rearward ends of said sills; a receptacle for the concrete materials rotatably mounted on said frame with its axis of rotation substantially'parallel' .to said. sills, said receptacle a dischargewopenmg: in its rearward end disposed between: said vertical frame members; means in said receptacle for agitating concrete materials therein and moving. the concrete :to and through said discharge opening; hinge devices carried: by the forward ends of the sills and provided with means for ready attachment thereof to the vehicle chassis, whereby the unit may be mounted on the latter for vertical swinging movements between a. normail horizontal mixing position and a rearwardly-upwa-rd:inclined discharging position; means carried by said unit frame forso moving the-unit, comprising a hoist device disposed adjacent each of said vertical frame members, connections between the upper ends of said hoist devices and said from members pivot-ally supporting the. devices on such members, and pivotalmea-ns carried by the lower ends of said devices and readily attachable. to the chassis, said'upper pivotal connections being substantia-lly in the horizontal plane of the center of gravity of the receptacle when loaded, whereby said hoist devices may efiectively resist the torque developed by the rotatingreceptacle and increase the stability of the machine when the unit is elevated; and means for actuating said hoist devices simultaneously.

2. A self-contained concrete mixing or agitating unit for til-table mounting upon the chassis of aroad vehicle without modification of such chassis, said unit comprising aframe including a pair of transversely spaced longitudinal sills disposable directly upon said chassis, and similarly spaced vertical members extending updevices carried by the forward ends of the sills and provided with means for ready attachment thereof to the vehicle chassis, whereby the unit may be mounted on the latter for vertical swinging movements between a normal horizontal mixing position and a rearwardly-upward' inclined discharging position; means carried by the unit frame for so moving the unit, comprising an extensible hoist device adjacent and substantially paralleling the outside of each of said vertical frame members, connections between. the upper ends of said hoist devices and said frame members pivotally supporting the devices on such members, and pivotal means carried by thelower ends of said devices and readily attachable to the chassis, said upper pivotal connections being substantially in the horizontal plane of the center of gravity of the receptacle when loaded. whereby said hoist devices may efiectively resist the torque developed by the rotating receptacle and increase the stability of the machine when the unit is elevated; means carried by thev unit frame for actuating said hoist devices simultaneously; and means carried by the unit frame for controlling actuation of said devices.

3. Apparatus as specified in claim 1, wherein the hinge devices for connecting the unit to the chassis comprise a member disposed transversely of the forward end of the vframe, means for readily rigidly attaching said member to "the vehicle chassis, and pivotal connections between such member and the forward ends of the longitudinal sills of the frame.

Apparatus as specified in claim I, wherein the pivotal means carried by the lower ends of the hoist devices comprise a member disposed transversely of the rearward end of the unit frame, means for ready rigid attachment of such member to the vehicle chassis, and pivotal connections between said member and the lower ends of the hoist devices.

BERNARD F. DEVINE. LOUIS G. HILKEMEIER.

REFERENCES CIT-ED The following references are of record in the file of this patent.

UNITED STATES. PATENTS 

